Telephone-receiver.



A. STROMBERG.

TELEPHONE RECEIVER.

APPLICATION FILED OUT. 2, 1906.

9 1 0,603 Patented Jan. 26, 1909.

ALFRED STROMBERG, OF CHICAGO, ILLINOIS.

TELEPHONE-BE CEIVEB.

Specification of Letters Patent.

Patented Jan. 26, 1909.

Application filed October 2, 1906. Serial No. 337,082.

To all whom it may concern:

Be it known that I, ALFRED STROMBERG, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented a new and useful Improvement in Telephone-Receivers, of which the following is a specification.

My invention pertains to telephone receivers, and has as its object the production of a receiver in which. a predetermined separation is readily and definitely attained between the diaphragm and the magnet pole pieces, and in which also the diaphragm is provided with dam ing and strengthening means to improve t e life and efficiency of the diaphragm.

'In my improved receiver, I mount the magnet pole pieces in a metal mounting cup, aline thefaces of the pole pieces with the edges of the mounting cup, then place the diaphragm over the edges pf the cup with an intervening distancewasher of proper thickness to produce proper separation between thecenter of the diaphragm and the faces of the pole pieces; this distance washer is clamped upon the edge of the diaphragm,

thereby becoming a part thereof, and by weighting and strengthening the edges of the diaphragmproduces a damping efi'ect in the diaphragm when the receiver is in use, and

- very greatly strengthens the diaphragm against accidental. injury when the receiver is taken apart for inspection or repairs.

In receivers of ordinary construction,-

where the diaphragm isclamped diroctlybetween the shell and the ear piece, the diaphragm is often "buckled by the twisting action necessary to bring the ear ece prop-- erly upon its seat against the aphragm. This is particularly true wherethe face of the shell against which .the diaphragm rests is not exactly in a plane or where the diaphragm is not of uniform thickness.

By my invention no twistin action whatever is brought to bear u on t e diaphragm roper, and therefore I e iminate the likeliood of a buckled diaphragm which would result in inefficiency in'the operation of the receiver. p v

In the sheet of drawings accompanying this specification, Figure 1 shows a view of'my improved receiver with the cap and diaphragm removed; Fig. 2 shows a sectional view of the complete receiver on the line 2 of Fig. 1; and

Fig. 3 shows a sectional view of the complete receiver on the line 3 of Fig. 1. v

In constructing the receiver here illustrated, the non-magnetic metal cup 10 is perforated to receive both ends of the permanent magnet 11, and screws 12, 13 and 14; the poles of the permanent magnet 11 are recessed to take the extension pole pieces 15 and 16 respeetively, bearing the magnet coils 17 and 18 respectively, the screws 12 and 13 acting with threads in the extension pole pieces 15 and 16 to lock permanent magnet, pole pieces and mounting cup rigidly together. Screw 14 holds in place the insulating block 19, carrying terminals 20 and 21; 22 is aninsulating washer adapted to hold the terminal pieces 20 and 21 in alinement and prevent accidental contact with conducting portions of the receiver structure.

The mounting cup, magnet, coils and pole pieces thus assembled are finished by grinding or turning off the edge of the cup 10 and the faces (or outer ends) of the pole pieces 15 and 16, thus bringing the faces of the pole pieces into accurate alinement with the edges provided with a rim, flange or distance ring 24, which in assembly is interposed between the face of the diaphragm 23 andthe edges of the mounting cup 10 and which thus holds the center of the diaphra m away from the faces of the ole pieces a istance accurately determined hy the thickness of the distance ring or washer 24 in that portion of it which lies between the diaphragm andthe edges of the mounting cup.

The rubber case, consisting of parts 25 and 26, is placed in position as shown surrounding fir finish-to the receiver as a whole. To further improve the receiver thus constructed, the distance rin 24 is spun over the edge of the diaphragm 2 so that it forms a strengthening member for the diaphragm, and also places the diaphragm under restraint to prevent or subdue the natural vibrations of the diaphragm whenvibrated by magnetic variations caused by electric speech currents through the coils 17 and 18.

I. do not wish to limit myself to the exact details'herein illustrated and described, as I understand that many modifications may be made without departing from the spirit or scope of my invention.

thpnlparts above described, clamping them y together, and giving a desirable outer 9 of the mounting cup 10.' Diaphragm 23 is ICC Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is: I

1. In a telephone receiver, a diaphra m 5 With a reinforced edge, said reinforced e ge con'sistin of aring of brass spun upon the edge of t e diaphragm, substantially as described. a

2. In a telephone receiver, 'a diaphragm 0 with a reinforced edge, said reinforced edge consisting of a ring of metal spun upon the diaphragm and forming a reinforcing ring upon each side of the diaphragm, substantially as described. 1

Signed by me at Ohica 0, county of Cook, 15 and State of Illinois, in t e presence of two witnesses. I

ALFRED STROMBERG.

Witnesses:

DAVID SJHULFIszI, HARRIET L. SMITH. 

